KIEV (Reuters) - At least four civilians were killed and several wounded by explosions at a village checkpoint in rebel-controlled territory in eastern Ukraine on Wednesday, the Organization for Security and Cooperation in Europe (OSCE) said.
There were conflicting accounts of the incident.
A news agency linked to Russian-backed separatists, quoting a senior rebel official, said six people were killed, including a pregnant woman and her unborn child, as a result of shelling from Ukrainian armed forces.
The Ukrainian military denied that, saying it had not returned fire despite being attacked by rebels in the area.
Fighting between the separatists and Ukrainian government troops has increased sharply despite calls to observe a year-old peace agreement, according to the OSCE.
The February 2015 Minsk ceasefire deal failed to completely halt the conflict that is now in its third year. Both sides accuse the other of violating the terms of the truce -- which includes a pullback of heavy weapons -- and casualties among soldiers or civilians are reported almost daily.
Twenty Ukrainian soldiers were reported killed in March -- the army's highest monthly death toll since August. In April, 17 Ukrainian troops have been killed so far.
Reporting by Natalia Zinets, writing by Matthias Williams, editing by Angus MacSwan